Change of Mechanical Properties during Dissolution Process in Soluble Granular Soils

Mechanical properties of engineering soils in earth structures or foundations may be influenced by the dissolution of soluble mineral. This paper addresses the evolution of the physical properties during dissolution of soluble particulate media. Two types of specimens including sand-salt mixtures and photoelastic-ice disk mixtures were used to investigate the changes of the granular soils from micro- to macro-scale. The dissolution was carried due to the saturation of the sand-salt mixtures or the melting of ice in photoelastic-ice disk mixtures. The measurements of shear wave velocities are implemented in sand-salt mixtures by using bender elements installed along the specimens. A system of strain gauges is installed on the side of the planar specimens to observe total response due to the melting of the ice disks. Particulate parameters consisting of force chain, local void and coordination numbers, and the horizontal force of the planar specimens of photoelastic disks and ice disks are monitored during ice dissolution. Experimental results show that the shear wave velocity decreases, then increases to a stable value, during salt dissolution. However, after dissolution the velocities are smaller than those before dissolution. The shear wave velocity in the upper non-wetted layer is slightly affected under the dissolution of the lower layer. Photographic images of photoelastic disk-ice mixtures show that the force chain, local void, and coordination number considerably change during dissolution. This Study demonstrates the correlation among the change of shear wave velocity, the total response and the particle parameters due to dissolution.